Method of high-temperature treatment of compounds



R. E. STANTON Nov; 3, 1953 METHOD OF HIGH-TEMPERATURE TREATMENT OF COMPOUNDS Filed May 25, 1948 INVENTOR.

ROBERT E. STANTON BY (L... M MMM fiwr A M HIS A TTORNEYS.

Patented Nov. 3, 1953 METHOD OF HIGH-TEMPERATURE TREAT- MENT OF COMPOUNDS Robert E." Stanton, Denver, Colo. I Application May 25, 1948, Serial No. 29,047

This invention relates to heating and heat transferring apparatuses and it relates more particularly to a heating apparatus for promoting the reaction between hydrocarbons and other reactive compounds, the cracking of hydrocarbons and other chemical reactions. More particularly, it relates to an apparatus wherein pebbles, preferably formed of surface active materials and the like, may be more efficiently heated prior to delivery into a reaction chamber wherein they are used for promoting the reaction by heat transfer. a

It has been suggested heretofore that ceramic pebbles and the like may be continuously fed through a furnace where they areheated and then delivered into a reaction chamber where they are used to heat materials supplied to the chamber. As the pebbles give up theirheat, they are discharged continuously from the reaction chamber and returned to the top of the furnace to be reheated and delivered in a continuous stream into the reaction chamber.

The prior devices have not been very efficient in the heating of the pebbles for they have been designed primarily so that they are heated by contact with heated combustion products. Due to the fact that ceramic materials are poor conductors, contact with the heated gases is insufficient to raise them efficiently to a desired temperature throughout and to make the best use of the heat supplied to the heating furnace.

An object of the present invention is to provide a more efficient system of heating the peb- 2 Claims. (c1. 12 63-42) I bles in a device of the character described above so that more efficient use of the heat of combustion is obtained. I

Another object of the invention is to provide a system wherein the pebbles are heatedby radiant heat at about flame temperature as well as by contact with heated products of combustion.

Other objects and advantages of the process will become apparent from the disclosure of a typical apparatus embodying the present invention.- In accordance with the present invention, I have provided a heating and reaction system of the type described generally above wherein a fuel is introduced into and only partially burned in one or more mufiles communicating with the interior of the furnace. The fuel and combustion supporting gas are supplied at a sufficiently high velocity to permit only part of the fuel to burn within the muflle, the remainder of the fuel flowing into the mass of pebbles within the furnace chamber to be burned in the interstices between the pebbles. In this way, the pebble's in the bot tom of the furnace adjacent the outlets of the muflles are subjected to radiant heat of combustion at flame temperature while the pebbles above this combustion zone are preheated by the heat of the combustion gases flowing upwardly through the body of pebbles.

It has been recognized that ceramic pebbles are, in themselves, somewhatsurface active, and that the fue1 will burn on surfaces of the pebbles. ciently. and the radiant heat at the surfa'ceof the pebbles raises their temperature very quickly. The pebbles so heated are delivered to the reaction chamber where they give up their heat and are recirculated, as described above. v

e For a better understanding of the present invention, reference may be had to the accompanying drawing, in which the single figure is a view in front elevation of a typical system embodying the present invention with the furnace or heating portion of the system shown partly in section and the reaction chamber shown in vertical section to disclose details thereof. The

heating. and reaction system disclosed in the drawing includes an elongated furnace shell or chamber I0 which may be providedwith a steel jacket and a refractory lining. The lower end of the chamber I ll is provided with a tapered portionl I which communicates by means of a passage [2 with the upper end of a reaction chamber 13. The reaction chamber l3 may consist of a steel or alloy shell which may be lined with refractory material, if desired. Thepebbles flow from the furnace l0 through the passage 12 into the reaction chamber l3 and are discharged continuously from the latter through thejre stricted neck portion [-4 onto an endless metal conveyor IS. The conveyor l5 delivers the pebbles into the bottom of an upright conveyor housing I6 where the pebbles are picked up by means of a bucket conveyor l6, delivered to the top of the furnace'chamber l0 and discharged into it by means of a chute IT. The upper end of the furnace I0 is provided with a flue l8 fordischarging of flue gases. andmay also be provided with a blow off valve l9.

The structure described generally above is substantially conventional.. .The novelty of the present apparatus resides primarily in the heating'and burner elements "for heating the pebbles in the furnaces. The heating system includes one or more muffies 20, each of which is provided-with pearshaped chamber 2| therein havingenlarged outer end portion and narrow neck portion-communicating with the interior of the furnace. The burner 22; through which fuel gas is supplied, extends into the enlarged portionof the chamberso that apart of the fuel is burned-with the air. supplied by means of the pipe 23 within the chambers! l. I have found that most efficient heating, is obtained by maintainingthe fuel .gas andair velocities near 'or above the-limit of flarne propagation velocity so that only a minor portion of "the fuel is actually In this way,lthe fuel is burned very efli- J 3 burned within the muille chambers 2|. In a typical installation, using methane as the fuel, the velocity of the gases may be about one foot per second. with other fuels, slightly higher or lower velocities may. be. used to permit ignition and combustion of the fuel. Preferably, the

fuel and air are admitted substantially in the.

proportions which are required stoighipmetrical ly for perfect combustion, thereby e1 excess air which might produce an oxidizing atmosphere. For this reason, the mixture. must It will be understood that the system described above can be varied substantially in its capacity and that different kinds of fuel can be burned in sys 1 Therefore, t e form of the invention descri .aboge sh u d considered as illustrative and not as limiting the SGQDB of the following claims.

be passed through the muflles and mixing valves v if the fuel and air are mixed before introduction into the muiiies, at a speed exceedingthat of flame propagation to avoid spontaneous combus- Q! fla h Q9 93 1 The unburned fuel flows, into the. furnace where the fuel air mixture. is burned directly. in

contact with, the. pebbles. It, is highly important hat h a ewsmixtw sli iil j burned. t tices between the pebbles so that a he n er-i Matt ns e! n. W9 at apn qximat fl m mpera ure. lna amq er ain. re i stqiv News iszh. r u table an us a Peb l Q mn e lum ua il qon a d fire clay, etc., havejthe property of catalytically assisting combustion, it will be apparent that aw. widest ombu io of t e wa obtained 1. We

The combustion products are appreciably cooled after yielding a large part of their heat to the. pebbles by radiant heat transfer. However, the heated combustion gases transfer additional heat to the pebbles by convection and contaet. The rate and efliciency of the heat transfor to the pebbles depends upon the velocity of the flowing gases. On this'account, the upper part of the furnace preferably is formed in such.

a manner as to provide a progressively decreasing. cross-sectional area so that a relatively uniform gas velocity through the pebbles can be maintained despite the progressive decrease inv volume due to cooling. This effect is produced by tapering the upper portion of the furnace chamber a shown in the drawings.

It has been found that, in the present systern, the burning fuel yields up almost 65% of its total recoverable heat in the form of radiant heat and the remainder is in the form of convective heat. In this way. app oximately 700 B. t, u. can be transferred for each pound of pebbles circulated in an hour if the rate of circulation is, such that the entire pebble bed is circulated once every forty-five minutes. Pebble temperatures of 160.0 E. can be readily attained by the use of the present system with great economy in the fuel burned.

The aboye-desoribed system may be used for promotion of many different types of reactions,

such as, for example, the production of carbon disulfide, as disclosed in my copending application Serial No, 29,046 filed May 25, 1948, the

cracking of hydrocarbons and the reaction of hydrocarbons and other reactive compounds. As disolosed in my copending application Serial No, 29,046 a hydrocarbon gas such as methane may be introduced into the reaction chamber I; through the manifold 24 while another reagent such as molten sulfur can be introduced into the mass of pebbles through the perforated pipes 25. ($513.01. the Q blQS ma h @qated. t a "M 52 ge t l t od q th u h nozzle 2 1 an: qwc s i. o the. f rn an 'q variations of the means for introducing the reassats w l se; to t ese ski ed. in. the ar lcla mi 1, 4. method of heating chemical compounds to promote reactions therebetween comprising continuously introducing ceramic pebbles into the top of a reaction zone from a heating zone above it, and returning the pebbles from the botreaction zone to the top of the heating zone, introducing air and fuel into a combustion ham er. @619 sa d. Wil 25 09$; 41'' Q. 2 9% 1911 hat, onl a mino portion 9; u l ymen. n h gentl men chamb r ta se l't a e a e -Q the, air a d 49. dis sxeins' a sem nars Q i i-s1. h twenties. smash nd he ai ra. e avmbastisa theme: at 99! ab propa atio elo ity is. ea heat as said. eat n w b es.

r ater 'si ban. a d. c embi ti i e? h at. sai Pebbles at. 1am; teammate.-

2. e memos. a! he in wimp, a t ve. ea s Pebb es. 19x nxqmsiivs QbifiQ I Q i ar n su ply n sexiest sa ire. assia. s a s csn a ws to 1.. a t a qa t en. q e r m a. fat ess shave it. saturate the bblflu 9, he. an .1. he te ace. item. the a iphi f eaction 2 mp s. qlzn i s ee she fi ii sunp st n a. simm r i s' n t i chamber outside of said furnace and sesame e t n i h. i 2 12 55 1 re ed fth i ans r be n si ni e ha bfi at e et su iq sn h e ps an? firbpafifidnre 91 is b m. nl a. ar 9 fii om n. hambe @2 be e rem n d the fuel and the gas, discharging said remnants ofthe fuel, the gasahd the combustion products from the chamber through said restricted in: sage at a velocity above sam propagation 'velocity and burning said remainder ofthe fuel in the furnace in the interstices between said pebbles to heat them at flame temperaturaaiid thereby form additional combustion productsfi'owing up wardly through said pebbles, and 'maintflning the velocity of the combustion product's substan tially constant as they fiow upwardly through the furnace. i

M sses-as C t d. a, h l o t is patent 333755. ATENFQ me a sameness In ust ia ol eat. tion, page 5.6.

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